Replacing Rigid Brake Lines

[0586slb]

The last three inches of brake line on each side at the front has corroded to mush. I have obtained new lines and see there is a manifold behind the left headlamp where they connect to. The left front brake line is easy; pass it in through the headlamp opening, behind the strut and it's there.

 

However, the right front line looks a nightmare. How much dismantling is requires to get that one in? It looks as though it goes behind the coolant hoses - then round the back of the 'tub'. A 'technician' at our OPC said you have to drop the front suspension/subframe?

 

Any help please?

[JFP in PA]

The last three inches of brake line on each side at the front has corroded to mush. I have obtained new lines and see there is a manifold behind the left headlamp where they connect to. The left front brake line is easy; pass it in through the headlamp opening, behind the strut and it's there.

 

However, the right front line looks a nightmare. How much dismantling is requires to get that one in? It looks as though it goes behind the coolant hoses - then round the back of the 'tub'. A 'technician' at our OPC said you have to drop the front suspension/subframe?

 

Any help please?

 

You tech is pretty much correct; these lines were never meant to be serviced with the car assembled, so there is quite a bit of work involved.

[Jeff8529]

Hi,

I read your Boxter brake line replacement, I am about to consider doing all lines on my 986 , can you give me any advice on what the pitfalls are did you manage to get over the issue on the RH side?

Any advice or pictures would be appreciated.

Thank you

Jeff,

Livingston

Scotland

[Hilux2400]

For some years I have made up my own brake lines with a flaring tool and using non-steel tubing.  I have not yet made any for my 996, but I have done for other and older cars.  It works well and it's easy.  I also have a pipe bender for small dia pipe and a selection of nipples, which must be fitted before flaring takes place. There are also mid run joints that can be made up when it's only necessary to re-make a flare near a fitting.  The pipe that I used is copper based and very malleable so quite tight bends are possible without kinks occurring.

[JFP in PA]

Hi,

I read your Boxter brake line replacement, I am about to consider doing all lines on my 986 , can you give me any advice on what the pitfalls are did you manage to get over the issue on the RH side?

Any advice or pictures would be appreciated.

Thank you

Jeff,

Livingston

Scotland

 

First, welcome to RennTech :welcome:

Do not even think about doing brakes lines unless you have a proper set of metric flare fitting wrenches; without these you will round over the hex fittings:

 

[JFP in PA]

For some years I have made up my own brake lines with a flaring tool and using non-steel tubing.  I have not yet made any for my 996, but I have done for other and older cars.  It works well and it's easy.  I also have a pipe bender for small dia pipe and a selection of nipples, which must be fitted before flaring takes place. There are also mid run joints that can be made up when it's only necessary to re-make a flare near a fitting.  The pipe that I used is copper based and very malleable so quite tight bends are possible without kinks occurring.

 

I would be cautious about using non-steel tubing on modern braking systems.  Cooper used to be fine on older braking systems, which operated at much lower pressures than modern systems with anti-lock and stability management systems.  While easy to work with, they could be soft enough to cause the flares to fail under pressure at the exact moment you need them most.

[Hilux2400]

 

For some years I have made up my own brake lines with a flaring tool and using non-steel tubing.  I have not yet made any for my 996, but I have done for other and older cars.  It works well and it's easy.  I also have a pipe bender for small dia pipe and a selection of nipples, which must be fitted before flaring takes place. There are also mid run joints that can be made up when it's only necessary to re-make a flare near a fitting.  The pipe that I used is copper based and very malleable so quite tight bends are possible without kinks occurring.

 

I would be cautious about using non-steel tubing on modern braking systems.  Cooper used to be fine on older braking systems, which operated at much lower pressures than modern systems with anti-lock and stability management systems.  While easy to work with, they could be soft enough to cause the flares to fail under pressure at the exact moment you need them most.

 

That's an interesting point.  I use piping made from a copper- nickel alloy, which apparently has the same burst pressure as steel tubing of about 19,000 psi.

 

I have used it successfully on older vehicles, but not on any car currently less than 15 years old.  On the 15 year old vehicle (not a Porsche), which I still own it is performing well. I used it to replace a corroded steel brake line that burst under severe braking when the vehicle was less than 8 years old. This is the second time I have had brake failure on this model of vehicle.  On both occasions the corroded steel pipe failed at a point above the fuel tank where road debris accumulates. The cupro-nickel pipe in this location does not corrode and I consider it to be a better option if it does not corrode and sustains the correct pressure. I notice that two of my local garages also uses cupro-nickel pipe for replacement.

 

If what you say is right about its inadequacy to sustain pressure, I need to investigate this further. Is there any guidance I could refer to on this topic?

[JFP in PA]

 

 

For some years I have made up my own brake lines with a flaring tool and using non-steel tubing.  I have not yet made any for my 996, but I have done for other and older cars.  It works well and it's easy.  I also have a pipe bender for small dia pipe and a selection of nipples, which must be fitted before flaring takes place. There are also mid run joints that can be made up when it's only necessary to re-make a flare near a fitting.  The pipe that I used is copper based and very malleable so quite tight bends are possible without kinks occurring.

 

I would be cautious about using non-steel tubing on modern braking systems.  Cooper used to be fine on older braking systems, which operated at much lower pressures than modern systems with anti-lock and stability management systems.  While easy to work with, they could be soft enough to cause the flares to fail under pressure at the exact moment you need them most.

 

That's an interesting point.  I use piping made from a copper- nickel alloy, which apparently has the same burst pressure as steel tubing of about 19,000 psi.

 

I have used it successfully on older vehicles, but not on any car currently less than 15 years old.  On the 15 year old vehicle (not a Porsche), which I still own it is performing well. I used it to replace a corroded steel brake line that burst under severe braking when the vehicle was less than 8 years old. This is the second time I have had brake failure on this model of vehicle.  On both occasions the corroded steel pipe failed at a point above the fuel tank where road debris accumulates. The cupro-nickel pipe in this location does not corrode and I consider it to be a better option if it does not corrode and sustains the correct pressure. I notice that two of my local garages also uses cupro-nickel pipe for replacement.

 

If what you say is right about its inadequacy to sustain pressure, I need to investigate this further. Is there any guidance I could refer to on this topic?

 

 

You would need to find two data points about the cooper tubing you are using: burst pressure and tensile strength, and then compare them to the steel alloy used in the factory lines.  Burst pressure is obvious, but less obvious is how well the cooper would stand up under tensile loads (basically stretching).  Because the flare process can actually thin the metal at the flare, it ability to stand up to tensile loads becomes important at these higher line pressure, particularly when automated pulse pressure systems (ABS, PSM, etc.,) come into play.

 

Corrosion of the mild steel lines has always haunted these cars, which is why there is an aftermarket using stainless steel.

[Hilux2400]

 

 

 

For some years I have made up my own brake lines with a flaring tool and using non-steel tubing.  I have not yet made any for my 996, but I have done for other and older cars.  It works well and it's easy.  I also have a pipe bender for small dia pipe and a selection of nipples, which must be fitted before flaring takes place. There are also mid run joints that can be made up when it's only necessary to re-make a flare near a fitting.  The pipe that I used is copper based and very malleable so quite tight bends are possible without kinks occurring.

 

I would be cautious about using non-steel tubing on modern braking systems.  Cooper used to be fine on older braking systems, which operated at much lower pressures than modern systems with anti-lock and stability management systems.  While easy to work with, they could be soft enough to cause the flares to fail under pressure at the exact moment you need them most.

 

That's an interesting point.  I use piping made from a copper- nickel alloy, which apparently has the same burst pressure as steel tubing of about 19,000 psi.

 

I have used it successfully on older vehicles, but not on any car currently less than 15 years old.  On the 15 year old vehicle (not a Porsche), which I still own it is performing well. I used it to replace a corroded steel brake line that burst under severe braking when the vehicle was less than 8 years old. This is the second time I have had brake failure on this model of vehicle.  On both occasions the corroded steel pipe failed at a point above the fuel tank where road debris accumulates. The cupro-nickel pipe in this location does not corrode and I consider it to be a better option if it does not corrode and sustains the correct pressure. I notice that two of my local garages also uses cupro-nickel pipe for replacement.

 

If what you say is right about its inadequacy to sustain pressure, I need to investigate this further. Is there any guidance I could refer to on this topic?

 

 

You would need to find two data points about the cooper tubing you are using: burst pressure and tensile strength, and then compare them to the steel alloy used in the factory lines.  Burst pressure is obvious, but less obvious is how well the cooper would stand up under tensile loads (basically stretching).  Because the flare process can actually thin the metal at the flare, it ability to stand up to tensile loads becomes important at these higher line pressure, particularly when automated pulse pressure systems (ABS, PSM, etc.,) come into play.

 

Corrosion of the mild steel lines has always haunted these cars, which is why there is an aftermarket using stainless steel.

 

Thanks JFP, I'll see what I can find out.

[tcora]

 

Corrosion of the mild steel lines has always haunted these cars, which is why there is an aftermarket using stainless steel.

 

 

JFP: I have found lots of folks selling braided stainless flex hoses for Boxsters (I'm familiar with this from motorcycling), but I can't seem to find stainless replacements for the hard lines.

 

I have at least one rusted out hard line to my rear brakes to deal with (hidden corrosion where the forward and aft section join just under the driver's seat and, yes, I plan to replace both lines regardless).

 

Admittedly, I got 12 years out of the set currently on the car, so I'm not too entirely upset about going to a new set of mild steel lines, but still - any reference to sources for stainless hard lines you can think of?

 

Thanks.

Edited December 13, 2015 by tcora

[JFP in PA]

Companies like Eastwood and Stainless Brakes sell stainless steel brake line tubing in rolls (usually around 25 ft. in length).  They also sell line end fittings.  Because of the complex bends in the factory lines, I don't believe you can find pre-bent units off the shelf.  You are going to need to extract your OEM mild steel lines and fabricate stainless replacements one at a time.

[tcora]

JFP: Thanks. Looking at the bends and how the lines are routed, I think I'll take the conservative route and stick with the OEM mild steel lines as replacements. Another 12 years wouldn't be so bad, and now that I know that the lines in this location are prone to corroding, I'll pay extra attention to rinsing the winter salt out of that area.

[JFP in PA]

JFP: Thanks. Looking at the bends and how the lines are routed, I think I'll take the conservative route and stick with the OEM mild steel lines as replacements. Another 12 years wouldn't be so bad, and now that I know that the lines in this location are prone to corroding, I'll pay extra attention to rinsing the winter salt out of that area.

 

You could also coat the new OEM lines to help limit the impact of winter salt.

[JPSummers]

Need to replace my hard brake lines from the ABS Unit to the splitter block and to both rear wheels. Anyone have a write up, video, photos, instructions on how they navigated this. Left side appears straight forward, more or less. Right Rear looks like a nightmare to route the line to. Yes, I have Flare Wrenches!

[Loren]

There is a special bleeding procedure in PIWIS (not sure about Durametric) that bleeds the ABS pump by running the pump and opening and closing the valves.

[JFP in PA]

Durametric will also do the ABS bleeding process.

 

As for routing the new hard lines, while I do not have any tips of videos to share, and having done similar jobs on other brands of vehicles, I can tell you that some hard lines are installed while the vehicle is bare chassis, resulting in the lines sometimes needing to be cut out of the car in sections as they cannot be pulled out whole unless the car is again disassembled.  When we run into these types of applications, we resort to nickel copper (DOT approved) line that is malleable and can be snaked into position and hand formed to match the suspect line.  This process requires having the necessary flaring tooling and line ends to create the replacement line, but one of the biggest advantages of using the nickel copper lines (besides the ease of shaping) is that they will never rust. 😉

[tcora]

On 3/5/2024 at 7:14 PM, JPSummers said:

Need to replace my hard brake lines from the ABS Unit to the splitter block and to both rear wheels. Anyone have a write up, video, photos, instructions on how they navigated this. Left side appears straight forward, more or less. Right Rear looks like a nightmare to route the line to. Yes, I have Flare Wrenches!

I did this job a couple years ago. Yes, the line to the right rear is a total bear. Patience is a virtue!